As of August 2011, if you've read this then you probably know more about how human values actually work than almost every professional metaethicist on Earth. The general lesson here is that you can often out-pace most philosophers simply by reading what today's leading scientists have to say about a given topic instead of reading what philosophers say about it.

Do philosophers actually talk about human motivation in the descriptive behavioral summary sense? (Or are you talking about experimental philosophers? But you do mention metaethicists...) In particular, while it might be the case that metaethicists could benefit from knowing this stuff, are metaethicists among the philosophers who one shouldn't learn from on this topic, do they write about it (in the descriptive, as opposed to the prescriptive/normative sense)?